Polyoxymethylene moulding compositions with improved heat stability and stability against discoloration

US6191222A · kind A · utility

Assignee

• Degussa-Huels AG · DE

Inventors

• Bruno Keller · Zürich, CH
• Stephanie Schauhoff · Frankfurt, DE
• Klaus Dorn · Kettwig, DE
• Hartmut Alt · Wächtersbach, DE
• Dietrich Michelchen · Niederrodenbach, DE

Key dates

• Filing date: Aug 7, 1998
• Grant date: Feb 20, 2001
• Expiry date: Aug 7, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L59/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Polyoxymethylene moulding compositions of the invention comprise PA1 (i) at least one polyoxymethylene homo- and/or copolymer, PA1 (ii) at least one conventional additive and PA1 (iii) at least one polymeric plastics material as an additive for improving the heat stability, and are distinguished in that PA1 (iii) is a copolymer which is obtainable by polymerization in bulk of a mixture of PA2 A) 60-90 parts of one or more (meth)acrylates, PA2 B) 10-40 parts of one or more (meth)acrylamides, PA2 C) per 100 parts of A)+B), >0.2 to 5 parts of molecular weight regulator and PA2 D) per 100 parts of A)+B), up to 2 parts of lipophilic free radical polymerization initiators, and in that PA1 the moulding composition comprises (iii) in an amount of 0.01 to 2 parts, based on the sum of (i)+(ii) where all the amounts relate to parts by weight (wt/wt) and A) and B) together must give 100 parts. By the use of relatively highly regulated bulk co- or terpolymerization for stabilizing POM moulding compositions, advantages over the use of emulsion or suspension bead polymerization result in the heat stability, in the stability against discoloration and/or in the residual monomer contents of POM moul…